Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.util.*;
import java.io.*;

public class Main {
	public static void main(String args[]) {new Main().run();}

	FastReader in = new FastReader();
	PrintWriter out = new PrintWriter(System.out);
	void run(){
		work();
		out.flush();
	}
	long mod=1000000007;
	long gcd(long a,long b) {
		return b==0?a:gcd(b,a%b);
	}
	void work() {
		int n=in.nextInt();
		int m=in.nextInt();
		int[][] A=new int[n][m];
		int[] col=new int[m];
		int[] row=new int[n];
		int[] sumC=new int[m];
		int[] sumR=new int[n];
		Arrays.fill(col, 99999999);
		Arrays.fill(row, 99999999);
		for(int i=0;i<n;i++) {
			for(int j=0;j<m;j++) {
				A[i][j]=in.nextInt();
				if(A[i][j]+A[0][0]!=A[i][0]+A[0][j]) {
					out.println(-1);
					return;
				}
				sumR[i]+=A[i][j];
				sumC[j]+=A[i][j];
				row[i]=Math.min(row[i], A[i][j]);
				col[j]=Math.min(col[j], A[i][j]);
			}
		}
		int r=0,c=0;
		for(int i=0;i<n;i++)r+=row[i];
		for(int j=0;j<m;j++)c+=col[j];
		if(m>n) {
			out.println(r+sumR[0]-row[0]*m);
			for(int i=0;i<n;i++) {
				for(int k=0;k<row[i];k++) {
					out.println("row "+(i+1));
				}
			}
			for(int j=0;j<m;j++) {
				for(int k=row[0];k<A[0][j];k++) {
					out.println("col "+(j+1));
				}
			}
		}else {
			out.println(c+sumC[0]-col[0]*n);
			for(int j=0;j<m;j++) {
				for(int k=0;k<col[j];k++) {
					out.println("col "+(j+1));
				}
			}
			for(int i=0;i<n;i++) {
				for(int k=col[0];k<A[i][0];k++) {
					out.println("row "+(i+1));
				}
			}
		}
	}
	
}



class FastReader
{
	BufferedReader br;
	StringTokenizer st;

	public FastReader()
	{
		br=new BufferedReader(new InputStreamReader(System.in));
	}

	public String next() 
	{
		if(st==null || !st.hasMoreElements())
		{
			try {
				st = new StringTokenizer(br.readLine());
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return st.nextToken();
	}

	public int nextInt() 
	{
		return Integer.parseInt(next());
	}

	public long nextLong()
	{
		return Long.parseLong(next());
	}
}